Magnetic, superconducting and electron-boson properties of GdO(F)FeAs oxypnictidesстатьяИсследовательская статья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 10 августа 2018 г.
Аннотация:We performed comprehensive studies of nearly optimal fluorine-substituted GdO(1−x)F(x)FeAs oxypnictide superconductors with Tc = 48−53K. Specific heat measurements revealed a sharp peak at T = 3.5 K that shifts to lower temperatures with magnetic field increase. This peak corresponds to an antiferromagnetic ordering in Gd^3+ ion sublattice and may indicate coexistence between superconducting and magnetic orderings. Andreev transport through artificially made constriction demonstrated two channels for the carriers from the band(s) with the large superconducting gap as well as from those with the small gap. As expected, the presence of a transport channel with the bands mixing (Δ_L + Δ_S) was not detected. Using intrinsic multiple Andreev reflections effect (IMARE) spectroscopy, we determined two superconducting gaps, Δ_S ~ 2.7 meV, and Δ_L ~ 11.6 meV. The reproducible fine structure in the dI(V)/dV spectra of the Andreev contacts (satellites of the main subharmonic gap structure for Δ_L) was interpreted as caused by a resonant emission of bosons with the energy ε_0 = 12−15 meV ~ Δ_L + Δ_S during the process of multiple Andreev reflections (MAR) for normal carriers in Δ_L-band(s) transport channel.